I. Field of the Invention
The present invention relates to an electrical connector assembly for termination of coaxial cable leads enabling rapid attachment to and detachment from a user board of a very large number of signal leads while ensuring an acceptable level of controlled impedance from the coaxial cable to the user board.
II. Description of the Prior Art
Requirements of backplane interconnections for electronic data processing and telecommunications applications call for ever increasing densities of electrical leads to accommodate an ever larger number of signals within a given unit of space. At the same time, the space limitations are ever decreasing and this combination has the undesirable effect of increasing noise potential by reason of the increased density of the signal leads. At the same time, it is necessary to maintain a matched impedance from the signal wire, through the region of the interconnection, and into the printed circuit board (PCB) or other form of circuitry with which the signal leads are being terminated. Typical of the problem being faced, and solved, by the present invention is the ability to achieve a standard 50 ohm impedance level for a defined density of leads for which it was only previously possible to obtain a 37 ohm impedance for lead density which was substantially less dense. Previously known small diameter coaxial contacts (for example, contacts having a diameter of 0.100 inches) generally used insulation material for the dielectric. This resulted in a lower impedance value. In contrast, the present invention employs air as the dielectric thereby achieving a higher impedance in a smaller space and utilizes other expedients to achieve positive mating engagement of a very large number of contacts within a limited space.